Unlockables
Hidden Duelists
After Everyone gets their 6th Locator cards, but before boarding the airship for the finals there are two hidden duels you can participate in:
Duel With Magnum - Go to the Aquarium. Mai will tell Magnum that she will marry him if he can defeat you in a duel.
Duel With Bandit Keith - Go to the Pier. As soon as you enter the first screen go right, into the building. Bandit Keith will be waiting.